The present invention disclosed herein relates to an apparatus for treating a substrate, and more particularly, to an apparatus for treating a substrate by using plasma and a plasma boundary limiter unit used therein.
In general, semiconductor manufacturing processes may be classified into a variety of processes such as a deposition process, a photolithography process, an etching process, a polishing process, and a cleaning process. Among these processes, the deposition process or the etching process treats a substrate by using plasma. A portion of a substrate treatment apparatus using plasma may include a confinement ring that confines plasma so that the plasma within a process chamber stays in a vertical upper space of a wafer during the process.
Generally, a confinement ring is disposed to surround a vertical upper space of a substrate. Also, the confinement ring includes an integrated body having a circular ring shape. The confinement ring may be provided in plurality. Here, the plurality of confinement rings are vertically spaced apart from each other. A distance between the confinement rings is relatively narrow to prevent plasma from leaking therebetween. However, in the case where the confinement rings having the above-described structure are used, a plasma leakage prevention effect is not high. Also, when the confinement rings having the above-described structure are used, it may be difficult to control plasma density for each region in inner regions of the confinement rings.
Also, the confinement rings interfere with a moving path of a substrate when the substrate is loaded into or unloaded from the process chamber. Thus, the confinement rings move to a standby position at which the confinement rings do not interfere with the moving path of the substrate when the substrate is loaded into or unloaded from the process chamber by a ring driver. Thus, since the confinement rings move to the standby position before or after an opening for loading or unloading the substrate is opened, a large number of processes is needed. Also, since the ring driver for moving the confinement rings is provided, the apparatus may be complicated in structure. Also, since the ring driver vertically moves all of the confinement rings, a large load may be applied to the ring driver.